A prospective cohort study of Norplant use in the immediate postpartum period among asymptomatic HIV-1-positive women was conducted in Bangkok, Thailand. The objectives of this study were to evaluate side effects and menstrual patterns of the Norplant system in this group. A total of 88 asymptomatic HIV-1-positive mothers were recruited for this study. All of them voluntarily accepted the use of the Norplant implant as a contraceptive method immediately postpartum. Their mean age was 24.9 years. Most of them had completed primary school. The follow-up period was 24 weeks. There were eight participants lost from the study because of loss of contact. Irregular bleeding was the most common menstrual pattern in these participants. The major side effects were headache, followed by hair loss. No subject terminated Norplant use during the study period. The Norplant implant appears to be safe and well tolerated in asymptomatic HIV-1-positive parturients when inserted immediately postpartum.